The American Burn Association has reported that each year approximately 450,000 burn injuries receive medical treatment in the U.S. Skin burns are classified into 4 grades of severity during triage, which in turn determines their distinct course of clinical treatment. For example, superficial partial-thickness burns can heal spontaneously over a 2- to 3-week period, whereas deep partial-thickness and full-thickness burns require excision and surgical skin grafting procedures. However, the accuracy rate of the current clinical assessment technique used to differentiate between burn grades is limited to 64-70%, often necessitating several skin grafting operations per patient over the course of treatment. Non-invasive and highly-accurate assessment of burn wounds can alter the management course, reduce the length of hospital stay and improve the overall recovery of the burn patient, while also reducing the cost of care. Based on our previous empirical observations of the sensitivity of the coherent terahertz (THz) time-domain spectroscopy to the water content of the tissue, as well as to scattering by the density of normal skin structures, we propose the following novel hypothesis: Partial-thickness burns that heal spontaneously in 2-3 weeks will differ significantly in their terahertz signatures from wounds that do not heal. We will address this hypothesis from the following approaches: 1. We will use standardized porcine burn models to determine the efficacy of the THz modality in burn characterization against histological assays. 2. Given the important role of deep dermal structures in the skin regeneration process, we will quantify the intactness and biological viability of cells that are responsible for reepithelialization in the vicinity of hair follicles and sweat glands of each burn using vitality assays. We will test the statistical correlation between this histological measure of skin regeneration and the terahertz time-domain spectroscopy measurements to determine a potential relationship for burn healing likelihood based on early THz predictions. 3. We will conduct dosimetry and safety studies in normal porcine skin models to establish that exposure to terahertz light is safe for human studies. 4. In collaboration with the Harborview Regional Burn Center at the University of Washington, we will conduct a pilot human study in order to investigate the utility of the terahertz modality in burn assessment during the early post-injury period.